How to Fix 0xc0000420 BSoD on Windows?

Hi, my Windows PC keeps crashing after boot with a 0xc0000420 blue screen. Sometimes apps won’t load, and the system becomes unresponsive. I’ve heard it could be due to corrupt system files, a damaged Windows image, or conflicts with a second OS.

What’s the best way to fix this? Any tips for safe mode, SFC/DISM scans, or recovering data if the PC won’t boot?

Thanks!

Tagged: Windows 11

System/ OS Errors

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Mira Lennox Lennox

Participant

October 8, 2025 at 5:44 am

Start by booting into Safe Mode (hold Shift + Restart from the login screen → Troubleshoot → Advanced → Startup Settings → Safe Mode). Once there, run sfc /scannow in an admin Command Prompt to check for corrupt files, then DISM /Online /Cleanup-Image /RestoreHealth to repair the Windows image. If Safe Mode won’t load, use a Windows 11 installation USB to access the recovery environment and run the same commands from Command Prompt. For data recovery, you can attach the drive to another PC or use a Linux live USB to copy important files before attempting repairs. If system files are heavily damaged, an in-place upgrade/repair install from the USB is often the safest fix without wiping your data.

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